He warned MSPs and their staff to be cautious when opening emails from external sources following the attack.

Users were informed the repeated log-in attempts could mean some are locked out of their email accounts.

In an email to staff on Tuesday, Sir Paul said: "The Parliament's monitoring systems have identified that we are currently the subject of a brute force cyber-attack from external sources.

"This attack appears to be targeting parliamentary IT accounts in a similar way to that which affected the Westminster Parliament in June. Symptoms of the attack include account lockouts or failed log-ins.

"The Parliament's robust cyber security measures identified this attack at an early stage and the additional security measures which we have in readiness for such situations have already been invoked. Our IT systems remain fully operational."

Users of the parliamentary email system have been asked to update passwords to ensure they are robust.